%I #10 Mar 08 2022 02:10:00

%S 0,7,7,1,4,1,8,1,4,5,7,7,8,4,1,8,1,4,7,7,7,7,4,1,8,1,4,2,7,7,4,4,1,8,

%T 1,4,2,7,7,2,4,1,8,1,4,4,7,7,5,4,1,8,1,4,4,7,7,7,4,1,8,1,4,8,7,7,5,4,

%U 1,8,1,4,1,7,7,3,4,1,8,1,4,6,7,7,1,4,1,8,1,4,5,7,7,8,4,1,8,1,4,7,7,7,1,4,1,8,1,4,8,7,7,4,4,1,8,1,4,2,7,7

%N a(n) = A061039(n) mod 9.

%C Is the number 0.77141814577... rational? Note groups of 4,1,8 at positions 7, 16, 25, 34, 43 etc.; also 7,7 positions 4, 13, 21, 31, 40, 49 etc.

%C From Paschen spectrum of hydrogen.

%C The number 6 appears at positions n=84, 159, 327, 402 etc.; the number 3 at n=78, 165, 321 etc; the number 0 at n=3, 240, 246 etc. - _R. J. Mathar_, Feb 28 2009

%C Starting with a(7) the pattern {4, 1, 8, 1, 4, b(n), 7, 7, c(n)} is repeated with b(n) and c(n) containing numbers zero to nine. - _G. C. Greubel_, Mar 08 2022

%H G. C. Greubel, <a href="/A146322/b146322.txt">Table of n, a(n) for n = 3..5000</a>

%F a(n) = A061039(n) mod 9.

%t Mod[Numerator[1/9 - 1/(Range[3, 150])^2], 9] (* _G. C. Greubel_, Mar 08 2022 *)

%o (Sage) [numerator(1/9 - 1/n^2)%9 for n in (3..150)] # _G. C. Greubel_, Mar 08 2022

%Y Cf. A061039.

%K nonn,less

%O 3,2

%A _Paul Curtz_, Oct 30 2008